Studies are underway to examine the genetic factors contributing to smoking initiation, nicotine dependence, and inability to quit. Other studies use DNA array technologies to map nicotine-induced alterations in the brain. By providing a better understanding of the biological mechanisms involved in nicotine addiction, this unfolding body of genetic research is expected to fuel developments in pharmacogenetics, to create new genetic tests, and ultimately, to provide the basis for innovative strategies for smoking cessation and preventive interventions. Translating the results of genetic research into public health or treatment programs will require the resolution of a host of complex ethical, legal, social, and policy issues. The "geneticization" of smoking may cast additional stigma on smokers, or shift responsibility for addiction away from the cigarette (and the tobacco industry) and onto individuals' genetic make-up. Crucial issues will accompany testing: Who should be considered at risk? Will racial groups be targeted? How will access to services be affected? Should we use psychotropic drugs to prevent smoking? The proposed research will combine empirical investigation with ethical and policy analysis, employing a range of methods: systematic review of the scientific literature and of tobacco industry documents, interviews with stakeholders, ethnographic research at scientific meetings, and a multi-disciplinary, national Advisory Board. The project's empirical aims are to: 1) assess the state of scientific knowledge about the genetic basis of smoking behaviors and susceptibility to nicotine addiction, 2) anticipate and characterize clinical and preventive health applications based on this knowledge, and 3) examine the emergence of a genetic understanding of smoking among key stakeholders in tobacco control. Informed by our empirical work, and in consultation with the project's Advisory Board, the ethical and policy aims are to: 4) delineate and evaluate the foreseeable impact of genetic explanations on existing smoking control policies, such as public health strategies and treatment programs, and, 5) identify and analyze key ethical, legal, and social consequences of a genetic understanding of smoking behaviors. The goal of the project is to provide policy makers with a clear understanding of the potential impacts and limitations of genetic research, ensure that genetics will integrate harmoniously in measures to reduce tobacco use, and contribute to the public policy debate about the genetics of addiction, by providing a comprehensive analysis of nicotine addiction - an illustration of the ethical complexities inherent in behavioral genetics research.